4. Clive Barker's Undying
The setup for this one is simple: a group of siblings drag a dusty old occult book to a group of standing stones situated near their estate, and do about exactly what you'd expect of a pack of over-enthusiastic children with no concept of foresight or genre tropes: they curse their family to a slow and agonizing death by reciting ancient Latin from the crumbling tome. Kids. You can't leave 'em alone for two seconds without worrying they're going to damn the entire house into oblivion. Fast forward to 1923 and we're introduced to paranormal investigator Patrick Galloway as he links up with his old friend and last surviving member of the Covenant family, Jeremiah. Turns out that poor ol' Jeremiah's siblings have come back from the dead and made it their un-life's mission to haunt the man into an early grave, leaving you to put an end to the family curse. Released way back in 2001, Undying utilized a dual wield system which presented the perfect counterpoint to the slower-pace associated with many horror titles - with a pistol in one hand and a spell in the other, Undying's captivating narrative was shot through with bursts of action that made excellent use of the game's mix-and-match style of gunplay while spewing forth a legion of monstrous creatures that could only have ever spawned from the darkest corners of Clive Barker's brain. Undying is easily one of the most dazzlingly inventive games of all time, so it's doubly unfortunate that the potential series fell victim to a curse of another kind: crappy sales.